Making rocket fuel on the Moon is another matter.
From what we know at the moment, there does not seem to be much carbon on the lunar surface. So, "rocket fuel" made there will probably be water that is separated into hydrogen and oxygen by something like electrolysis using solar energy as the power source. So, it would fuel rockets that use liquid hydrogen, such as the Centaur second stage currently used on the Atlas and Vulcan launch vehicles. (See
https://en.wikipedia.org/wiki/Centaur_(rocket_stage) )
So, we have been using that technology since the 1960s, but, as Wikipedia says, liquid hydrogen "has significant handling difficulties." It needs to be a lot colder than liquid oxygen or liquid methane, and it has weird properties like climbing the sides of the tanks. It is also quite good at leaking through the tiniest openings, including pores in metallic walls.
The initial Centaur launches created some spectacular explosions during launches. And re-ignition of the engines did not always work, initially. So, making hydrogen propellant and using it on the Moon has some substantial risks.
But, "cold" on the Moon may be more easily done than here on Earth. And it is one of the most efficient rocket propellants. The exhaust gas is pure water, but being non-polluting probably has no value on the Moon.
So, if we really do find enough water on the Moon to expend it as rocket propellant, then our trips beyond will actually be done using solar energy, but first transformed into chemical energy.